The seeming inexorable shift toward consumers buying on the web, instead of at stores, isn’t likely to be affected by Thursday’s Supreme Court ruling that online retailers have to pay sales tax, experts say.

However, the ease of having goods delivered to their door has long since surpassed tax calculations for many consumers, said Bob Hetu, vice president of retail for analyst firm Gartner.

“At this point people are really making their purchasing decisions based much more on convenience. I don’t think they’re making decision on sales taxes,” he said.

What comes now will be a scramble as online sellers struggle to understand what they'll be required to do and those that hadn't been paying state sales taxes figure out how they'll make it happen.

“We started receiving calls within 30 minutes (of the ruling) by folks who had a question, and they’ve been pouring in all day,” said Mark Faggiano, CEO of TaxJar, a company that automates sales tax collection for e-commerce companies.

Larger online companies have long had their own internal tax compliance divisions that take care of all this. Smaller companies that had been mostly ignoring online taxes in states where they didn't have warehouses or some kind of physical presence are the ones who will be most affected.

They'll most likely turn to some of the multiple companies that offer services that automate the process of charging the bewildering array of taxes levied at the city, county and state level. Those ever-changing laws can vary based on the item being purchased, and most of the rules were written when everyone bought everything from shoes to microwave ovens from the store down the street.

A playing field that didn't start out level

While the ruling is a boon to state coffers and is being touted as "leveling the playing field" between online and traditional store-based retailers, it's in many ways an issue between big and small e-commerce companies. The large ones stopped fighting requirements to charge local sales tax several years ago, so it's no longer a problem for them.

“Amazon has got well over 50 percent of the e-commerce market. They’re charging tax. Walmart is the next biggest. They’re charging tax, so the majority of what’s happening online is already happening,” Faggiano said.

At the same time, many smaller companies "have been vehemently against this for years, and it will have a material impact on many of them,” said Sucharita Kodali,principal analyst for e-commerce at Forrester Research.

The biggest hit for newer online retailers is that they won't get the runway of opportunity that Amazon and other early online companies did when no one was paying sales tax online.

In the early days of internet retail, the lack of taxes was a real lure for consumers. That first-mover advantage helped eBay, Amazon and others gain significant market share and cut deeply into store-based retailers.

Now, new online retailers into the market won't have the same advantage to help them get off the ground.

The ruling puts the small retailer at a disadvantage compared with big, sophisticated online retailers, said Scott Peterson, vice president of U.S. tax policy at Avalara, a sales tax compliance software company.

None of the tax changes will take effect immediately. The Supreme Court remanded the case back to South Dakota's state Supreme Court, so there will be at least a few more weeks before it goes into effect. And presumably, other states will be watching to see what South Dakota does, Faggiano said.

“Hopefully, most companies will not overreact. The first thing a retailer should do is talk to their attorney,” he said.